[1] yes, recently a thread talked right about curl and openssl vs.
gnutls, but evidently i didn't see what i call a general
consensus.

IMHO provide both, ssl and gnutls.

I can only agree.

Even when libcurl works identically good using either library, OpenSSL and
GnuTLS differ not only license-wise but they also have features of their own
and bugs of their own. Limiting the libcurl offer to use only one of them will
cause grief at some point in some camp(s), that's for sure.